The present disclosure relates to semiconductor devices, and more particularly, to solar photovoltaic cells.
A photovoltaic cell is a component in which light is converted directly into electrical energy.
A heterojunction photovoltaic cell is one in which two dissimilar materials are used to generate band offsets in order to induce charge separation between generated electrons and holes.
A heterojunction photovoltaic cell comprises at least one light-absorbing layer and a charge transport layer, as well as two electrodes. If the converted light is sunlight, the photovoltaic cell is a solar cell.
For solar photovoltaic cells, one would ideally want to use low-cost, non-toxic and abundant source materials and process these materials at low temperature on inexpensive substrates. The mobilities of such materials are often poor. For example, thin film copper oxide (CuO) has a nearly ideal band gap (1.6 eV) for a solar photovoltaic device, but has a low mobility (<10−1 cm2/V-sec) when oxidized at about 400-500° C.
Heterojunctions of dissimilar semiconductors are often used to create solar cells. The fabrication process for junctions of dissimilar materials is usually complex, and the manufacturing cost is high.
In this regard, state-of-the-art heterojunction solar cells between dissimilar inorganic semiconductors require very careful engineering in order to avoid carrier recombination at interface states. Often the devices are made using epitaxial techniques in order to insure the quality of the interface. Further, defects in the bulk must be minimized so that electron-hole pairs can propagate to their respective electrodes, which must be separated by at least the absorption length of incident photons.
Thus, the need exists for a photovoltaic cell having a heterojunction of dissimilar semiconductors, which is easily fabricated from low-cost, non-toxic, abundant source materials. The semiconductors are dissimilar inorganic semiconductors that allow for electrons and holes to propagate to the electrodes of the photovoltaic cell.
The present disclosure contemplates a new and improved solar photovoltaic cell and method which overcomes the above-referenced problems and others.